Friday, May 2, 2014

Flat Roof Repair

With the gloomy forecast of four days of rain and thunder showers, it was time to tear into the roof and find out what was going on. 

Flat roofs are not recommended for the simple fact that water pools up and doesn't shed off the roof. The problem is accentuated when previous homeowners attempt to expand an area by tying prior construction to newer remodels.

No matter how straight things are when the remodel is when constructed, valleys soon form from differing seasonal movement and settling between old construction and new. Our roof is no exception as four remodels all meet at one corner over the old bathroom, the area we are tearing into.

Every step we take into this project, we find more evidence of prior leak issues, attempting patch work, and poor results. 

We will fix the roof today with some patching compound and rubber sealant on the EPDM roof which will last another couple of years but will design a low sloping hip style standing seam roof to add in the future


  1. Dan,
    While I'll be the first to agree that many flat roofs are installed poorly, a properly installed EPDM roof will outlast any asphalt shingle. Unfortunately that "properly installed" part is often hard. Let me know if you have any issues or questions with installation. I'll be happy to show you how to get the most out of it.

  2. Completely agree. I'm not overly fond of EPDM but it excels at low-slope requirements. The issue with my roof is areas of zero drainage allowing the water to pool. Anything will leak if the water sits on it long enough. I knowledge is with historic systems, but I was under the impression that a zero-slope roof actually implied a slope under 3/12, very slight but still enough for the water to go somewhere.

    As for asphalt, it's a dirty word in my field.

    When the time comes, I'll frame it up a little bit in order to give it a little more slope and put a standing seam tin roof on it. I'll fold the seams a little taller than the normal 1 inch to allow room for the water coming down from the other pitch. The other option is to solder all the seams flat. I definitely would not install any shingles on a slope that low and the tin will hold up for 150+ years with proper maintenance.

    With that being said, would you mind if I contacted you later to ask about the patching material and sealer I'm using on the EPDM?

    Thanks. Dan

    1. Dan,
      Hit me up any time. I'll gladly help out however I can.

      A zero slope roof is an issue, though EPDM is the 2nd best membrane for it. Unlike asphalt, EPDM sheets do not degrade when left under water. Only the seams will, and even then they'll well outlast asphalt seams.

      For a roof which is completely impervious to standing water, you'll need a heat weldable membrane - PVC or TPO. While both more technical to install than EPDM, their heat welded seams are stronger than the sheets and both are unaffected by standing water.

      Besides roofing we've successfully used EPDM & TPO to line fountains. That's about as much standing water as a system will ever see.


Let me know what you think! Comments and suggestions are always welcome!